1. Field
Exemplary embodiments relate to optical zoom probes. In particular, exemplary embodiments relate, to an optical zoom probe which is capable of performing a close distance scan and an ultra-close distance scan.
2. Description of the Related Art
In the field of medical imaging, there are increasing demands for information about the surface of tissue (e.g., a human body or a skin), and technology for precisely taking a photograph of a plane section of a body part under the skin. In particular, since most cancers are generated under epithelial cells and propagated into hypodermal cells where blood vessels are present, damage may be drastically reduced if the cancers are detected early. In existing imaging technology, such as magnetic resonance imaging (MRI), x-ray computed tomography (CT), and an ultrasound, an internal plane section of a body part under the skin may be photographed. However, the image obtained from the plane section during photography has a low resolution, making it impossible to detect small sizes of early cancers. Further, in contrast with existing imaging technology, optical coherence tomography (OCT) in the related art uses light in contrast with existing imaging technology. Thus, a depth to which light penetrates a body part under the skin is only about 2˜3 mm. However, an image obtained using light has a resolution about ten times as high as the resolution of an image obtained using ultrasonic waves. Thus, recent OCT in the related art is useful in the diagnosis of early cancers, at approximately 50 to 100 μm. However, since OCT in the related art still provides low resolution, in comparison with microscopes, OCT fails to replace a biopsy and a histology, which are still used in determining cancers.
Instead of performing a biopsy, some OCT researchers in the related art have recently conducted research into real-time diagnosis of cancers inside tissue by combining the tomography characteristics of OCT with a high-resolution surface photographing method, such as a confocal microscope. However, an objective lens of a microscope needs an optical system with a high numerical aperture (NA) in order to obtain a high horizontal resolution. Further, OCT in the related art needs an optical system with a low NA, in which a light spot size in a depth direction is relatively uniform, i.e., a depth of focus (DOF) is large, in order to obtain depth information. Moreover, in contrast with an OCT mode, in an optical coherence microscopy (OCM) mode of the related art, a DOF is small in a z-axis direction. Thus, a longer DOF is required.